it'd actually be pretty insane if they went that route, such a sudden shift in tone would make me way more interested in this manga
There's a series that operates on such a timeframe, more or less, called
Tensei Shite High Elf ni Narimashitaga, Slow Life wa 120-nen de Akimashita.
The TL;DR version is that a dude gets reincarnated as an elf and just lazes about doing absolutely nothing for the first 120 years of his new life; eventually, he decides to go out and see the world, learn new things, and meet new people.
I eventually got tired of the time scale, but it would regularly have 5-10 year time skips; by the time I called it quits at Chapter 25, I think something like 30-40 years had passed since the first chapter and you could see how old the earlier characters had gotten.